1. Technical Field
The present invention relates to a printing apparatus, a lens sheet, and a printing method.
2. Related Art
There is known a technique that forms a print image on a lenticular lens having a number of cylindrical convex lenses (hereinafter, referred to as convex lenses) arranged in parallel, thereby realizing a stereoscopic vision when the print image is observed through the convex lenses. In order to realize such a print image, predetermined image processing is performed on the image data corresponding to the left and right eyes of humans, thereby creating image data for stereoscopic vision. When printing is performed based on the image data, a print image for stereoscopic vision is formed on a lens sheet.
In the stereoscopic image data, subdivided image data for visual observation by either the left and right eyes are alternately arranged. Therefore, when the print image is formed on the lens sheet, it is necessary to match the phases (the positional relationship between the convex lenses and the subdivided image data) of the convex lenses and the print image. If a deviation in the phase (position) occurs between the convex lenses and the print image, the print image may not be visible from directly in front of the lens sheet, but may only be visible in a slightly inclined state, thereby making it difficult for a user to visually perceive the picture. Moreover, if the picture is viewed at positions different from the optimum position through the convex lens, the picture may be distorted and thus the quality will be poor.
When the lens sheet is fabricated, the cutting positions in the width direction of the convex lenses at the periphery differ from time to time. For this reason, it is necessary to perform phase matching between the convex lens and the print image for each lens sheet. As a method for solving such a phase matching problem, for example, a technique is disclosed in JP-B-3471930.
According to the technique disclosed in JP-B-3471930, a plurality of identification images spaced at varying intervals are printed on a margin area of a lens sheet. However, in this technique, a user needs to determine or select the optimum one from the plurality of identification images through visual observation. Therefore, a lot of time must be spent observing and determining if there are many identification images.